The present invention relates to acceleration protective suits for pilots, and more particularly to an inflatable suit for protecting the pilot against the effects of acceleration experienced in high performance aircraft.
When an aircraft is in a sharp turn or climb from a horizontal or upright attitude, as when performing air combat maneuvers, its path describes a curve and the pilot experiences a force due to radial acceleration above the normal level of 1 G. High performance engine-airframe combinations may sustain turns exceeding 8 G's but the tolerance of an erectly seated pilot at these levels is limited both in magnitude and duration of the acceleration. The hydrostatic force on the longitudinal artery complex of the pilot causes blood to pool in the legs and seriously diminish in the head. In addition to discomfort and pain, the pilot may experience unconciousness or "blackout".
One system for attenuating the effects on the pilot for radial acceleration, is disclosed in U.S. Pat. No. 3,826,434 to Dr. Harald J. von Beckh entitled "Pelvis and Legs Elevating G-Protective Seat", issued July 30, 1974. The tilt of the seat is adjusted about a lateral axis passing through the pilot's head to place his body in a supine position normal to the vertical axis of the aircraft. This system may be used with a conventional type G-suit such as disclosed in U.S. Pat. No. 2,871,849 to J.D. Chatham et al for Body Constraining Suit for Aviators, issued Feb. 3, 1959, wherein the pilot is fitted with a body constraining G-suit that receives compressed air in inflatable bladders to constrain his legs and arms. The inflation pressure is regulated by a control valve solely as a function of the acceleration without regard to its direction and internal variations in suit pressure which may be brought on by bodily functions such as breathing and abdominal muscular activity. That is, the radial acceleration is a turn or climb is generally along the vertical axis Z of the aircraft, and the suit pressure will correspond thereto even though the pilot may be in a reclined position where the amount of G-suit constraint required is not as great as it would be if he were sitting upright. Consequently, the inflation pressure is excessive, and may cause unnecessary discomfort, and impair his performance.